1. Field of the Invention
The present invention relates to a pet waste absorption sheet intended to be spread on a floor, a bottom face of a tray-type pet toilet, or the like and a process for manufacturing the same.
2. Description of the Related Art
Typically, pet waste absorption sheets have a liquid-impermeable backsheet on a lower surface side, a liquid-permeable topsheet on an upper surface side, and an absorbent core disposed between the backsheet and the topsheet. Such pet waste absorption sheets are intended to be spread on a floor or the like with the lower surface directed downward, so that pets can step on the upper surface of the pet waste absorption sheet.
In a pet mat disclosed in Japanese Unexamined Patent Application Publication No. 2004-187597, the backsheet is a nonwoven fabric laminated with a waterproof film. The absorbent core, which lies on the backsheet, is a pulp layer covered with water absorbent polymer and further wrapped in a carrier tissue. The topsheet, which covers the upper surface of the absorbent core, is a nonwoven fabric. After absorption of urine discharged from dogs and cats, however, the pet mat of JP 2004-187597 tends to emit an offensive odor because no measures are taken.
In Japanese Unexamined Patent Application Publication No. 2004-242516, there is disclosed a deodorant for pets. In this invention, a spraying container is filled with a deodorant composition in liquid form and a deodorant composition in powder form. After a pet discharges waste onto pet litter, the deodorant of JP 2004-242516 can be sprayed over the pet litter. However, it is painful to spray the deodorant over the pet litter every time the pet discharges waste.
In Japanese Unexamined Utility-Model Application Publication No. H05-039258, on the other hand, there is disclosed a pet waste absorption sheet whose absorbent core contains microcapsules filled with perfume. The perfume is intended to emit an aroma smell through fine pores of the microcapsules. However, the perfume contained in the absorbent core is not sufficiently effective in deodorizing urine adhering to the topsheet. In the pet waste absorption sheet, the urine adhering to the topsheet emits an offensive odor such as ammonia odor when it evaporates from the topsheet.
In addition, the microcapsules contained in the absorbent core are liable to adhere to a conveyor or roller of a production line at a step of feeding the absorbent core onto the backsheet or bonding the topsheet to the upper surface of the absorbent core. This reduces the amount of perfume contained in the absorbent core to decrease yields. Moreover, since the perfume contained in the absorbent core easily comes into contact with the air during the manufacturing process, the deodorizing effect tends to decrease due to volatilization of the perfume during the manufacturing process.
Furthermore, the production line needs frequent cleaning to remove the perfume from the conveyor or roller. Particularly when another product is to be produced on the same production line as the pet waste absorption sheet with the perfume microcapsules, the whole production line needs cleaning, thereby increasing the steps for changeover.